1. Field of the Invention
This invention relates to arthroscopic tissue cutting and removal devices by which anatomical tissues may be cut and removed from a joint or other site. More specifically, this invention relates to instruments configured for cutting and removing soft tissue and hard tissue with both mechanical cutting means and electrosurgical cutting means.
In several surgical procedures including subacromial decompression, anterior cruciate ligament reconstruction involving notchplasty, and arthroscopic resection of the acromioclavicular joint, there is a need for cutting and removal of soft tissues as well as bone. Currently, physicians use two or more arthroscopic devices to perform such a procedure. For example, a mechanical shaver may used to cut soft tissue while a high speed bone burr may be used to remove bone. In addition, one or more RF probes may also be used to cut certain types of tissue, to contour tissue surfaces, or to coagulate and seal tissue.
A typical arthroscopic shaver or burr comprises a metal cutting member carried at the distal end of a metal sleeve that rotates within an open-ended metal shaft. A suction pathway for removal of bone fragments or other tissues is provided through a window proximal to the metal cutting member that communicates with a lumen in the sleeve.
When metal shavers and burrs “wear” during a procedure, which can occur very rapidly when cutting bone, the wear can be accompanied by loss of micro-particles from fracture and particle release which occurs along with dulling due to metal deformation. In such surgical applications, even very small amounts of such foreign particles that are not recovered from a treatment site can lead to detrimental effects on the patient health, with inflammation being typical. In some cases, the foreign particles can result in joint failure due to osteolysis, a term used to define inflammation due to presence of such foreign particles. A recent article describing such foreign particle induced inflammation is Pedowitz, et al. (2013) Arthroscopic surgical tools: “A source of metal particles and possible joint damage”, Arthroscopy—The Journal of Arthroscopic and Related Surgery, 29(9), 1559-1565. In addition to causing inflammation, the presence of metal particles in a joint or other treatment site can cause serious problems for future MRIs. Typically, the MRI images will be blurred by agitation of the metal particles caused by the magnetic field used in the imaging, making assessments of the treatment difficult.
Another problem with the currently available arthroscopic shavers is that mechanical cutting does not work well with some types of tissue. RF plasma-based electrosurgical cutting would be preferred, but reliable RF plasma shavers have not been developed.
Therefore, the need exists for arthroscopic shavers that can operate to cut and remove both soft tissue and bone tissue and further to remove bone tissue without the release of fractured particles and micro-particles into the treatment site. Further, there is a need for arthroscopic shavers that can use RF plasma for tissue resection. At least some of these objectives will be met by the inventions described below.
2. Description of the Background Art
Pedowitz, et al. (2013) Arthroscopic surgical tools: “A source of metal particles and possible joint damage”, Arthroscopy—The Journal of Arthroscopic and Related Surgery, 29(9), 1559-1565 has been discussed above. Co-pending, commonly assigned U.S. patent application Ser. No. 14/960,084 , filed on Dec. 4, 2015, and Ser. No. 14/977,256 , filed on Dec. 21, 2015, the full disclosures of which are incorporated herein by reference, have disclosures related to the present application. See also U.S. Pat. Nos. 6,149,620 and 7,678,069.